1. Field of the Invention
The present invention relates to lifting poles, aka gin poles, that are used to raise loads above structures such as radio towers too tall to reach with a crane, and more specifically, to an improved lifting pole assembly that is engineered to allow a lifting pole to be position in multiple tilted positions relative to the vertical plane and in multiple pivoted positions relative to the horizontal plane.
2. Prior Art
A gin pole is a supported pole which uses a pulley or block and tackle on its upper end to lift loads. The lower end is braced or set in a shallow hole and positioned so the upper end lies above the object to be lifted. The pole (also known as a “mast”, “boom”, and “spar”) is secured with three or more guys. These are manipulated to move the load laterally, with up and down controlled by the pulley or block. The gin pole is considered a form of derrick, called standing derrick or pole derrick, distinguished from sheers (or “shear legs”) by having a single boom rather than a two-legged one.
Gin poles are also used to raise loads above structures too tall to reach with a crane, as placing an antenna atop a steeple, and to lift segments of a tower atop one-another during erection. When used to create a segmented tower, the gin pole can be detached, raised, and re-attached to the just completed segment in order to lift the next. This process of “jumping” is repeated until the topmost portion of the tower is completed.
A disadvantage of prior art lifting poles, particularly in the segmented tower field, is that the lifting pole assembly is generally fixed to the tower structure with the lifting pole in a fixed vertical position. This fixed configuration limits the ability of the lifting pole in raising loads of certain dimensions and limits the location from which loads can be lifted. While the mounting position of the lifting pole can be altered to account for such variations, there is no known prior art lifting pole that can be quickly and easily adjusted in the field to alleviate such concerns.